Step 1
Cut one front piece and two back pieces from the fabric. Press a double 1in (2.5cm) hem to the wrong side along one long edge of each back piece. Pin and machine-stitch both hems in place, stitching close to the first pressed edge on each.
Step 2
Lay the front piece right side up on a flat surface, then place the back covers on top, right sides down, with raw edges even and the hemmed edges overlapping at the center. Pin, then baste the pieces together around all four sides. Machine-stitch a 5⁄8in (1.5cm) seam around all four sides.
Step 3
Remove the basting. Trim the seam allowances to 3/8 in (1cm), and snip off the corners of the seam allowances. Turn the pillow cover right side out. Carefully push out the corners using a sharp pair of scissors, and press the seamed edges flat. Insert the pillow form through the back opening, and smooth the back overlaps flat.
Step 4
If your pillow form is large, you may wish to sew snaps to the underside of the overlap and the right side of the underlap. This will stop the opening from gaping and keep the front nice and taut.
Step 5
Excerpted with permission from <a target="_blank" href="https://www.amazon.com/gp/product/1782494766/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1782494766&linkCode=as2&tag=craftfocom-20&linkId=cdae79c291e0e39e374c828bf96978eb">A Beginner's Guide to Making Curtains, Shades, Pillows, Cushions, and More: 50 step-by-step projects, plus practical advice on hanging curtains, choosing fabric, and measuring up</a>.